While this year’s vegetable garden is still fresh in your mind, make note of the problems and the successes in your garden journal. While weather is a huge factor in the overall success of the garden, there is little that one can do to control it. Weather conditions are often at the root of disease; indeed, it drives many of them. But there are some things that you can do to help control disease problems that may arise, rather than just reaching for a fungicide to treat the end result. Let the following points be a checklist for you as you manage your vegetable garden this year and as you plan next year’s garden:
1) Improve the soil
It always gets down to the health of the soil so have a soil test done to determine pH and what amendments (if any) are needed. Add compost and aged manure each year as this will encourage the mycorrhizae (beneficial soil fungus) and the soil micro organisms to achieve a healthy balance in the soil —your best insurance against disease. Use a mulch to conserve moisture and discourage weeds.
2) Choose resistant or tolerant varieties
Call your local county Cooperative Extension for a list of the varieties best suited for planting in New York State. This list has disease resistant and tolerant selections that are less likely to develop disease. Look at seed packets and plant labels for letter abbreviations that describe the resistance of a variety, for example, PM=powdery mildew resistant or tolerant, VF= Verticillium and Fusarium wilt resistant. Resistant varieties are not immune to disease, but much less likely to contract it.
3) Scrutinize plant and seed purchases
Start with the best plant material that you can find. Always examine transplants carefully for any signs of problems, either disease or insect. If in doubt, pass on the purchase. Using good quality seed and healthy transplants is the best way to start in the garden.
4) Site your garden in a sunny, well drained location
Six hours of direct sunlight is the minimum exposure for good vegetable growth. Shaded, poorly drained locations will result in spindly, weak growth that is prone to disease organisms. Yields will be low in less than ideal sites.
5) Allow for good air circulation
Space plants according to directions on the seed packet or the plant label. Allowing enough room for growth and air circulation reduces humidity and promotes rapid drying of plant surfaces, which helps to reduce the incidence of disease.
6) Use good sanitation practices
Start the season with sharp tools that are wiped regularly with a mild bleach solution or alcohol. A great tip from Bob Beyfuss, a retired CCE agent in Greene County: For tomato cages or other types of support, dip the bases in a disinfecting solution (5% bleach and one gallon of water) before setting them in the garden. This will greatly reduce the spread of tomato diseases common in the home garden. As the season progresses, remove any foliage that appears diseased and do not compost it. At the end of the season, clean and remove any debris from the garden to lessen the possibility of disease over-wintering and infecting new plants the following spring.
7) Water and fertilize correctly
Most plants require an inch of rain a week during the growing season. Keep track of rainfall and if it is less than an inch per week, supplement with drip irrigation such as a soaker hose. Avoid overhead irrigation as it can promote and spread disease. Feed your soil with compost but use a complete fertilizer at the time of planting; some plants will benefit from a second application as a side-dressing mid-season but be careful not to over-do.
8) Plant a fall cover crop
After fall clean-up, sow a cover crop such as annual (winter) rye which will grow in the fall and can be turned under the following spring. This will enrich the soil with a “green manure” that adds organic matter and helps with that all important soil balance of micro-organisms.
9) Rotate crops
For small gardens this is a challenge but it is important that rotation be done to whatever extent possible. Avoid successive planting of crop families such as crucifers (cabbage, broccoli, turnip, radish), curcurbits (melon, cucumber, squash, etc.), solanaceous (tomato, pepper, eggplant, potato), grasses (sweet corn, cover crops such as rye), legumes (bean, pea), and root crops (carrot, beet, onion). Successive planting of crop families over time will promote the build-up of disease in the soil.
Following these guidelines will help you to grow a healthy vegetable garden with less reliance on chemical fungicides and more emphasis on soil health. You may be surprised that following these steps may also lessen your garden maintenance chores and increase your enjoyment of the garden. Hopefully the yield will be better too!
Susan Pezzolla, Master Gardener Coordinator, Horticulture Educator. Cornell University Cooperative Extension. 24 Martin Road, Voorheesville, NY.